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557fc4a0 MK |
1 | /* |
2 | * Copyright (c) 2016 Qualcomm Atheros, Inc | |
3 | * | |
4 | * GPL v2 | |
5 | * | |
6 | * Based on net/sched/sch_fq_codel.c | |
7 | */ | |
8 | #ifndef __NET_SCHED_FQ_IMPL_H | |
9 | #define __NET_SCHED_FQ_IMPL_H | |
10 | ||
11 | #include <net/fq.h> | |
12 | ||
13 | /* functions that are embedded into includer */ | |
14 | ||
15 | static struct sk_buff *fq_flow_dequeue(struct fq *fq, | |
16 | struct fq_flow *flow) | |
17 | { | |
18 | struct fq_tin *tin = flow->tin; | |
19 | struct fq_flow *i; | |
20 | struct sk_buff *skb; | |
21 | ||
22 | lockdep_assert_held(&fq->lock); | |
23 | ||
24 | skb = __skb_dequeue(&flow->queue); | |
25 | if (!skb) | |
26 | return NULL; | |
27 | ||
28 | tin->backlog_bytes -= skb->len; | |
29 | tin->backlog_packets--; | |
30 | flow->backlog -= skb->len; | |
31 | fq->backlog--; | |
32 | ||
33 | if (flow->backlog == 0) { | |
34 | list_del_init(&flow->backlogchain); | |
35 | } else { | |
36 | i = flow; | |
37 | ||
38 | list_for_each_entry_continue(i, &fq->backlogs, backlogchain) | |
39 | if (i->backlog < flow->backlog) | |
40 | break; | |
41 | ||
42 | list_move_tail(&flow->backlogchain, | |
43 | &i->backlogchain); | |
44 | } | |
45 | ||
46 | return skb; | |
47 | } | |
48 | ||
49 | static struct sk_buff *fq_tin_dequeue(struct fq *fq, | |
50 | struct fq_tin *tin, | |
51 | fq_tin_dequeue_t dequeue_func) | |
52 | { | |
53 | struct fq_flow *flow; | |
54 | struct list_head *head; | |
55 | struct sk_buff *skb; | |
56 | ||
57 | lockdep_assert_held(&fq->lock); | |
58 | ||
59 | begin: | |
60 | head = &tin->new_flows; | |
61 | if (list_empty(head)) { | |
62 | head = &tin->old_flows; | |
63 | if (list_empty(head)) | |
64 | return NULL; | |
65 | } | |
66 | ||
67 | flow = list_first_entry(head, struct fq_flow, flowchain); | |
68 | ||
69 | if (flow->deficit <= 0) { | |
70 | flow->deficit += fq->quantum; | |
71 | list_move_tail(&flow->flowchain, | |
72 | &tin->old_flows); | |
73 | goto begin; | |
74 | } | |
75 | ||
76 | skb = dequeue_func(fq, tin, flow); | |
77 | if (!skb) { | |
78 | /* force a pass through old_flows to prevent starvation */ | |
79 | if ((head == &tin->new_flows) && | |
80 | !list_empty(&tin->old_flows)) { | |
81 | list_move_tail(&flow->flowchain, &tin->old_flows); | |
82 | } else { | |
83 | list_del_init(&flow->flowchain); | |
84 | flow->tin = NULL; | |
85 | } | |
86 | goto begin; | |
87 | } | |
88 | ||
89 | flow->deficit -= skb->len; | |
90 | tin->tx_bytes += skb->len; | |
91 | tin->tx_packets++; | |
92 | ||
93 | return skb; | |
94 | } | |
95 | ||
96 | static struct fq_flow *fq_flow_classify(struct fq *fq, | |
97 | struct fq_tin *tin, | |
98 | struct sk_buff *skb, | |
99 | fq_flow_get_default_t get_default_func) | |
100 | { | |
101 | struct fq_flow *flow; | |
102 | u32 hash; | |
103 | u32 idx; | |
104 | ||
105 | lockdep_assert_held(&fq->lock); | |
106 | ||
107 | hash = skb_get_hash_perturb(skb, fq->perturbation); | |
108 | idx = reciprocal_scale(hash, fq->flows_cnt); | |
109 | flow = &fq->flows[idx]; | |
110 | ||
111 | if (flow->tin && flow->tin != tin) { | |
112 | flow = get_default_func(fq, tin, idx, skb); | |
113 | tin->collisions++; | |
114 | fq->collisions++; | |
115 | } | |
116 | ||
117 | if (!flow->tin) | |
118 | tin->flows++; | |
119 | ||
120 | return flow; | |
121 | } | |
122 | ||
b43e7199 MK |
123 | static void fq_recalc_backlog(struct fq *fq, |
124 | struct fq_tin *tin, | |
125 | struct fq_flow *flow) | |
126 | { | |
127 | struct fq_flow *i; | |
128 | ||
129 | if (list_empty(&flow->backlogchain)) | |
130 | list_add_tail(&flow->backlogchain, &fq->backlogs); | |
131 | ||
132 | i = flow; | |
133 | list_for_each_entry_continue_reverse(i, &fq->backlogs, | |
134 | backlogchain) | |
135 | if (i->backlog > flow->backlog) | |
136 | break; | |
137 | ||
138 | list_move(&flow->backlogchain, &i->backlogchain); | |
139 | } | |
140 | ||
557fc4a0 MK |
141 | static void fq_tin_enqueue(struct fq *fq, |
142 | struct fq_tin *tin, | |
143 | struct sk_buff *skb, | |
144 | fq_skb_free_t free_func, | |
145 | fq_flow_get_default_t get_default_func) | |
146 | { | |
147 | struct fq_flow *flow; | |
557fc4a0 MK |
148 | |
149 | lockdep_assert_held(&fq->lock); | |
150 | ||
151 | flow = fq_flow_classify(fq, tin, skb, get_default_func); | |
152 | ||
153 | flow->tin = tin; | |
154 | flow->backlog += skb->len; | |
155 | tin->backlog_bytes += skb->len; | |
156 | tin->backlog_packets++; | |
157 | fq->backlog++; | |
158 | ||
b43e7199 | 159 | fq_recalc_backlog(fq, tin, flow); |
557fc4a0 MK |
160 | |
161 | if (list_empty(&flow->flowchain)) { | |
162 | flow->deficit = fq->quantum; | |
163 | list_add_tail(&flow->flowchain, | |
164 | &tin->new_flows); | |
165 | } | |
166 | ||
167 | __skb_queue_tail(&flow->queue, skb); | |
168 | ||
169 | if (fq->backlog > fq->limit) { | |
170 | flow = list_first_entry_or_null(&fq->backlogs, | |
171 | struct fq_flow, | |
172 | backlogchain); | |
173 | if (!flow) | |
174 | return; | |
175 | ||
176 | skb = fq_flow_dequeue(fq, flow); | |
177 | if (!skb) | |
178 | return; | |
179 | ||
180 | free_func(fq, flow->tin, flow, skb); | |
181 | ||
182 | flow->tin->overlimit++; | |
183 | fq->overlimit++; | |
184 | } | |
185 | } | |
186 | ||
187 | static void fq_flow_reset(struct fq *fq, | |
188 | struct fq_flow *flow, | |
189 | fq_skb_free_t free_func) | |
190 | { | |
191 | struct sk_buff *skb; | |
192 | ||
193 | while ((skb = fq_flow_dequeue(fq, flow))) | |
194 | free_func(fq, flow->tin, flow, skb); | |
195 | ||
196 | if (!list_empty(&flow->flowchain)) | |
197 | list_del_init(&flow->flowchain); | |
198 | ||
199 | if (!list_empty(&flow->backlogchain)) | |
200 | list_del_init(&flow->backlogchain); | |
201 | ||
202 | flow->tin = NULL; | |
203 | ||
204 | WARN_ON_ONCE(flow->backlog); | |
205 | } | |
206 | ||
207 | static void fq_tin_reset(struct fq *fq, | |
208 | struct fq_tin *tin, | |
209 | fq_skb_free_t free_func) | |
210 | { | |
211 | struct list_head *head; | |
212 | struct fq_flow *flow; | |
213 | ||
214 | for (;;) { | |
215 | head = &tin->new_flows; | |
216 | if (list_empty(head)) { | |
217 | head = &tin->old_flows; | |
218 | if (list_empty(head)) | |
219 | break; | |
220 | } | |
221 | ||
222 | flow = list_first_entry(head, struct fq_flow, flowchain); | |
223 | fq_flow_reset(fq, flow, free_func); | |
224 | } | |
225 | ||
226 | WARN_ON_ONCE(tin->backlog_bytes); | |
227 | WARN_ON_ONCE(tin->backlog_packets); | |
228 | } | |
229 | ||
230 | static void fq_flow_init(struct fq_flow *flow) | |
231 | { | |
232 | INIT_LIST_HEAD(&flow->flowchain); | |
233 | INIT_LIST_HEAD(&flow->backlogchain); | |
234 | __skb_queue_head_init(&flow->queue); | |
235 | } | |
236 | ||
237 | static void fq_tin_init(struct fq_tin *tin) | |
238 | { | |
239 | INIT_LIST_HEAD(&tin->new_flows); | |
240 | INIT_LIST_HEAD(&tin->old_flows); | |
241 | } | |
242 | ||
243 | static int fq_init(struct fq *fq, int flows_cnt) | |
244 | { | |
245 | int i; | |
246 | ||
247 | memset(fq, 0, sizeof(fq[0])); | |
248 | INIT_LIST_HEAD(&fq->backlogs); | |
249 | spin_lock_init(&fq->lock); | |
250 | fq->flows_cnt = max_t(u32, flows_cnt, 1); | |
251 | fq->perturbation = prandom_u32(); | |
252 | fq->quantum = 300; | |
253 | fq->limit = 8192; | |
254 | ||
255 | fq->flows = kcalloc(fq->flows_cnt, sizeof(fq->flows[0]), GFP_KERNEL); | |
256 | if (!fq->flows) | |
257 | return -ENOMEM; | |
258 | ||
259 | for (i = 0; i < fq->flows_cnt; i++) | |
260 | fq_flow_init(&fq->flows[i]); | |
261 | ||
262 | return 0; | |
263 | } | |
264 | ||
265 | static void fq_reset(struct fq *fq, | |
266 | fq_skb_free_t free_func) | |
267 | { | |
268 | int i; | |
269 | ||
270 | for (i = 0; i < fq->flows_cnt; i++) | |
271 | fq_flow_reset(fq, &fq->flows[i], free_func); | |
272 | ||
273 | kfree(fq->flows); | |
274 | fq->flows = NULL; | |
275 | } | |
276 | ||
277 | #endif |